Magma + Gels
This process creates fine particles by reacting inorganic solutions to form insoluble products.
precipitation of the dispersed phase
What is a magma containing 5% hydrated aluminum silicate?
bentonite magma
What are pressurized dosage forms that release a fine dispersion upon activation?
aerosols
Aerosols for asthma require particles of this approximate size.
<5 um
Aerosols improve _____ by protecting drugs from air, light, and moisture.
stability
This method forms magnesium hydroxide from magnesium oxide and water.
direct hydration
This property allows bentonite to swell up to 12× its volume.
hydration/swelling
The medium in which aerosol particles are dispersed.
gaseous medium
When are fine mists used in clinical settings?
When pulmonary delivery is needed
What is avoided with aerosol topical application?
mechanical irritation (rubbing)
These systems remain fairly uniform due to strong affinity between phases.
Magmas + Gels
What is thixotropy?
Bentonite magma exhibits this flow behavior above 4%.
This component helps expel the formulation from the container.
the propellant
What are the six routes of aerosol drug delivery?
pulmonary, nasal, lingual, skin, vaginal, rectal
Why are CFC propellants a major disadvantage?
Environmental concerns
What is required to do before administration due to settling over time?
Shaking the preparation
What is aluminum hydroxide gel?
A gel containing insoluble aluminum hydroxide used as an antacid.
What does the valve assembly (and actuator) control?
How the aerosol is delivered
What is hermetic sealing in aerosols?
An advantage that prevents contamination of remaining product.
These aerosols lose pressure as product is used
compressed gas aerosols
What is 2 NaOH + MgSO₄ → Mg(OH)₂ + Na₂SO₄?
The reaction used to prepare Milk of Magnesia.
This suspension contains ~7–8.5% Mg(OH)₂ and has pH ~10.
Milk of Magnesia
What are the four factors together determine drug delivery from aerosols.
the container, valve assembly, actuator, and propellant
This effect from propellants can soothe or irritate skin.
the cooling effect from volatilization
In this system, dip tube must stay in aqueous phase.
a three-phase aerosol system